The clandestine NROL-76 satellite launched one month ago by a Falcon 9 rocket is making a series of close passes by the International Space Station on Saturday, potentially coming as close as 12 Kilometers.

Three weeks have passed since the secretive NROL-76 satellite launched atop a Falcon 9 rocket. Now satellite trackers have gotten hold of the clandestine spacecraft operated by the U.S. National Reconnaissance Office in a Low Earth Orbit 400 Kilometers in altitude.

A SpaceX Falcon 9 rocket thundered away from Florida’s Space Coast on Monday on its first top-secret satellite delivery for the U.S. National Reconnaissance Office, operator of the country’s spy satellite fleet.

A SpaceX Falcon 9 rocket lifted off from Launch Complex 39A at Florida’s Kennedy Space Center on Monday, May 1st, 2017 on a classified mission to deliver the NROL-76 satellite for the U.S. National Reconnaissance Office.

SpaceX’s Falcon 9 is aiming for a Sunday liftoff from Florida’s Space Coast on the company’s first classified satellite delivery for the secretive National Reconnaissance Office in charge of operating all U.S. spy satellites.